When developing a handheld product, it is important to consider a number of factors that will affect the end-user. For example, the size and weight of the product must be kept down in order that a user is able to handle the product easily, and that the product does not cause discomfort to the user during use. Another important consideration is that of noise. It is preferable that a handheld product does not produce a level of noise that is unpleasant and/or uncomfortable during use. What is more, excessive noise could potentially be damaging to a user's hearing if the product is used regularly over a long period of time. It is often the case that additional soundproofing, for example foam, is included in a product in order to maintain an acceptable level of noise generated by the product. Alternatively, the motor can be run at a lower power to reduce the level of noise that it generates. Of course, neither of these solutions are particularly desirable. Additional components or materials such as foam will increase the cost of the product, and running the motor at a lower power will negatively affect the performance of the product.
In handheld products which contain motors, it is often the motor that contributes the most towards the weight of the overall product and also towards the noise of the product during use. In smaller, handheld products, it is usual for many components of the motor to be formed of plastics which are more lightweight than other alternative materials.